Over 1.3-kV β-Ga₂O₃ Vertical UMOSFET With High Concentration of N-Ion Implantation and Activation Annealing Temperature

In this article, we investigated the electrical characteristics of the high-voltage <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-gallium oxide (Ga2O3) vertical U-shaped trench gate MOSFETs (UMOSFETs) based on a current blocking layer (CBL) under varying nitrogen ions implantation concentrations and activation annealing temperatures. When the nitrogen ions implantation concentration is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times 10^{{19}}$ </tex-math></inline-formula> cm−3 and the activation annealing temperature is 1200 °C, the fabricated device achieved the highest breakdown voltage (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V} _{\text {br}}$ </tex-math></inline-formula>) exceeding 1.3 kV without field plates, while obtaining an <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small>-resistance (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R} _{\text {on}}$ </tex-math></inline-formula>) of 132.35 m<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega \cdot $ </tex-math></inline-formula> cm2. Additionally, at a nitrogen ions implantation concentration of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 10^{{19}}$ </tex-math></inline-formula> cm−3 and an activation annealing temperature of 1100 °C, the device achieved a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V} _{\text {br}}$ </tex-math></inline-formula> of 985 V, R<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text {on}}$ </tex-math></inline-formula> of 24.37 m<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega \cdot $ </tex-math></inline-formula> cm2, and a power figure-of-merit (PFOM) of 40 MW/cm2. Our findings indicate that the current blocking capability of the CBL and Vbr improved with the increase in nitrogen ions implantation concentration and activation annealing temperature, while an increase in device R<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text {ON}}$ </tex-math></inline-formula> was observed. Overall, this work demonstrates the potential for achieving high-performance <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga2O3 UMOSFETs with nitrogen ions implantation.